RNA splicing contributes to the generation of mature mRNAs of Borna disease virus, a non-segmented negative strand RNA virus.

We recently demonstrated that Borna disease virus (BDV) has a negative non-segmented single stranded (NNS) RNA genome, whose organization is similar to that of other members of the Mononegavirales order. However, we have also documented that in contrast to the rest of the NNS-RNA animal viruses, BDV replication and transcription occur in the nucleus of infected cells. Here, we provide evidence that BDV uses the host nuclear splicing machinery to generate some of the viral mRNAs, representing the first documentation of RNA splicing in NNS-RNA animal viruses. Possible implications of RNA splicing for the regulation of BDV gene expression are discussed.